Steady State and Transient Modeling for the 10 MWe SCO 2 Test Facility Program

Transcription

1 Steady State and Transient Modeling for the 10 MWe SCO 2 Test Facility Program Megan Huang, CJ Tang, Aaron McClung March 28, 2018 DOE NETL DE FE

2 Agenda SCO 2 Test Facility Program Overview Steady State Modeling Modeling Assumptions Optimization Parameters Initial Results Impact of Results Transient Modeling Conclusion DOE C & CBTL Workshop 2 Slide 2

3 SCO 2 Test Facility Program Funded by DOE NETL 6 year program started in October 2016 Design, construct, and build test facility in San Antonio, Texas 700 C or higher turbine inlet temperature 10 MWe net RCBC configuration Simple Cycle configuration also to be tested Objectives Demonstrate operability of SCO2 cycle Verify performance of components Show potential for producing lower COE Demonstrate potential and pathway for thermodynamic η > 50% in commercial applications DOE C & CBTL Workshop 3 Slide 3

4 Steady State Modeling: Overview Steady State Modeling Provides input for technical specifications for each equipment Component sizing and optimization based on a 10 MWe RCBC configuration with 715 C turbine inlet temperature 3 modeling tools used Ensures accuracy and repeatability of results Organization Gas Technology Institute General Electric Global Research Southwest Research Institute Steady State Modeling Tool Aspen Plus Aspen Hysys Numerical Propulsion System Simulation (NPSS) DOE C & CBTL Workshop 4 Slide 4

5 Steady State Modeling: Assumptions Thermodynamic property method: REFPROP Turbomachinery performance maps provided by GE Recuperator parameters: 5 C approach temperature 0.7 bar pressure drop per side Heat source pressure drop was 4 bar Initial piping pressure drops based on past GTI layout of a commercial scale plant DOE C & CBTL Workshop 5 Slide 5

6 Steady State Modeling: Aspen Models Net Plant Power = 6.5 MWe Cycle η = 30.8% Simple Cycle Pilot Plant Aspen Plus Model DOE C & CBTL Workshop 6 Slide 6

7 Steady State Modeling: Aspen Models Net Plant Power = 10.4 MWe Cycle η = 46.2% RCBC Pilot Plant Aspen Plus Model DOE C & CBTL Workshop 7 Slide 7

8 Steady State Modeling: Optimization Parameters 3 elements to achieving high cycle efficiency for a given net power output Maximizing turbine power production Minimizing compressor power Minimizing heat input into the system DOE C & CBTL Workshop 8 Slide 8

9 Steady State Modeling: Maximizing turbine power production Turbine power dependent upon: Inlet and outlet conditions Mass flow rate Turbine efficiency Turbine exit pressure needs to be high enough to ensure two phase flow does not occur at main compressor inlet 15% margin on the critical pressure applied in these initial models DOE C & CBTL Workshop 9 Slide 9

10 Steady State Modeling: Minimizing Compressor Power Compressor power dependent upon: Inlet and outlet conditions Mass flow rate Compressor efficiency Inlet guide vane (IGV) settings can be adjusted to vary compressor ratios and efficiencies Complicating factor for RCBC configuration is flow split between compressors, which affects efficiency DOE C & CBTL Workshop 10 Slide 10

11 Steady State Modeling: Minimizing Heat Input 2 factors 1 st factor: minimize mass flow rate through heater Dependent upon turbine flow function 2 nd factor: Achieve highest cold stream outlet temperature from high temperature recuperator (HTR) Minimize approach temperature in recuperators 5 C chosen DOE C & CBTL Workshop 11 Slide 11

12 Steady State Modeling: Initial Results 7 cases were modeled DOE C & CBTL Workshop 12 Slide 12

13 Steady State Modeling: Agreement Among 3 Models Results of the 3 models show good agreement for baseline case Differences less than 2% generally LTR heat duty difference is larger due to different pressure drop and approach temperature assumptions DOE C & CBTL Workshop 13 Slide 13

14 Steady State Modeling: Agreement Among 3 Models Off-design cases results show more disagreement Smaller difference in system level parameters, such as cycle efficiency or turbine power Larger difference in detail component performance, such as IGV setting Main reason for discrepancies is offdesign assumptions for recuperator performance and minor flow rate differences DOE C & CBTL Workshop 14 Slide 14

15 Steady State Modeling: Impact of Results DOE C & CBTL Workshop 15 Slide 15

16 Steady State Modeling: Impact of Results Performance losses due to increased pressure drop Initial piping + equipment pressure drop assumption Initial piping layout + equipment pressure drop Pressure Drop (bar) ~12 bar ~17 bar 2 cases modeled to determine impact 1. Maintain baseline compressor pressure ratios decreasing turbine pressure ratio Result: turbine pressure ratio dropped by 2.6%, cycle efficiency dropped by 0.9 points 2. Maintain turbine pressure ratio increasing compressor pressure ratios Result: compressor pressure ratios increased by 3-4%, cycle efficiency dropped by 0.2 points More work needed, but initial results show maintaining turbine pressure ratio is better for maintaining a higher efficiency DOE C & CBTL Workshop 16 Slide 16

17 Steady State Modeling: Impact of Results Performance losses due to recuperator approach temperature Increasing recuperator approach temperature reduced cycle efficiencies One exception: LTR approach temperature DOE C & CBTL Workshop 17 Slide 17

18 Transient Modeling: Overview Transient Modeling Results will provide insight into operational analysis for the facility 2 modeling tools will be used Ensures accuracy and repeatability of results Organization Gas Technology Institute General Electric Global Research/Southwest Research Institute Steady State Modeling Tool Flownex Numerical Propulsion System Simulation (NPSS) DOE C & CBTL Workshop 18 Slide 18

19 Transient Modeling: Next Steps Build/modify steady state models Benchmark these to Aspen Plus & Hysys models Develop and implement control system methodology Run analysis for various transient cases DOE C & CBTL Workshop 19 Slide 19

20 Conclusion Initial steady state analysis has been performed 3 different steady state modeling tools: Aspen Plus, Aspen Hysys, NPSS Initial results show good agreement among the models for overall performance Steady state results have been incorporated into technical specifications for the components Updates to steady state models in progress Transient modeling of the facility is in progress 2 modeling tools will be used: Flownex and NPSS Results will aid in the operational analysis for the facility DOE C & CBTL Workshop 20 Slide 20

21 Acknowledgement & Disclaimer Acknowledgement This material is based upon work supported by the Department of Energy under Award Numbers DE-FE Disclaimer This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. DOE C & CBTL Workshop 21 Slide 21

22 Thank you! Questions? Megan Huang Ching Jen Tang Aaron McClung DOE C & CBTL Workshop 22 Slide 22